Mount Isa (copper orebodies)
North-west Queensland, Mount Isa Inlier, Australia
Other hydrothermalCu
- Type
- Hydrothermal copper in silica-dolomite (Urquhart Shale)
Copper orebodies (1100, 1900 and 3000/3500 in the centre; 200, 400, 500, 650 and 700 at the periphery) in the silica-dolomite replacing pyritic shales of the Urquhart Shale, in contact with the Eastern Creek metabasalts; distinct from the nearby stratiform Pb-Zn-Ag orebodies. Copper sulfide sulfur (8 to 21 ‰) comes from reaction of a 34S-rich brine with light sedimentary pyrite: central siliceous orebodies are homogeneous, peripheral dolomitic ones heterogeneous. Mine coordinates.
δ34S in ‰ (per mil) Values of the same system
Standard : V-CDT
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| 12.7 ± 2.3 ‰ | 9.9 / 17.1 ‰ | 11 | chalcopyrite of the 1100 orebody Mean and standard deviation recalculated from 11 samples, Table 1. Separated by froth flotation and magnetic methods, purity generally better than 90 %. Central siliceous orebody, the most homogeneous; the 16.4 and 17.1 ‰ values come from level 19 (sphalerite veins, slate cut by quartz). | Andrew et al. (1989), Sulfur isotope systematics of copper ore formation at Mount Isa, Au… |
| 12.2 ± 1.7 ‰ | 9.8 / 17.4 ‰ | 20 | chalcopyrite of the 1900 orebody Mean and standard deviation recalculated from 20 samples, Table 1. Separated by froth flotation and magnetic methods, purity generally better than 90 %. | Andrew et al. (1989), Sulfur isotope systematics of copper ore formation at Mount Isa, Au… |
| 11.9 ± 1.9 ‰ | 8.8 / 13.8 ‰ | 5 | chalcopyrite of the 3000 and 3500 orebodies Mean and standard deviation recalculated from 5 samples, Table 1. Separated by froth flotation and magnetic methods, purity generally better than 90 %. Veins in shales and dolomitic breccias. | Andrew et al. (1989), Sulfur isotope systematics of copper ore formation at Mount Isa, Au… |
| 14.3 ± 2.8 ‰ | 8.8 / 21.1 ‰ | 29 | chalcopyrite of the peripheral orebodies (200, 400, 400-700, 500 and 650) Mean and standard deviation recalculated from 29 samples, Table 1. Separated by froth flotation and magnetic methods, purity generally better than 90 %. Orebodies with dolomitic gangue, more heterogeneous and 34S-richer, with higher values at their margins; K600 triplicate averaged. | Andrew et al. (1989), Sulfur isotope systematics of copper ore formation at Mount Isa, Au… |
| 15.9 ± 3.2 ‰ | 11.5 / 24.6 ‰ | 24 | pyrite II (coarse pyrite crystallised with chalcopyrite) Mean and standard deviation recalculated from 24 samples, Table 1. Separated by froth flotation and magnetic methods, purity generally better than 90 %. All orebodies; pyrite II-chalcopyrite pairs indicate equilibrium at about 100 to 300 °C. | Andrew et al. (1989), Sulfur isotope systematics of copper ore formation at Mount Isa, Au… |
| 11.4 ± 2.1 ‰ | 8 / 14.3 ‰ | 9 | pyrrhotite Mean and standard deviation recalculated from 9 samples, Table 1. Separated by froth flotation and magnetic methods, purity generally better than 90 %. All orebodies. | Andrew et al. (1989), Sulfur isotope systematics of copper ore formation at Mount Isa, Au… |
| 12.9 ± 1 ‰ | 12.2 / 13.6 ‰ | 2 | sphalerite from veins of the 1100 orebody Mean and standard deviation recalculated from 2 samples, Table 1. | Andrew et al. (1989), Sulfur isotope systematics of copper ore formation at Mount Isa, Au… |
| 9.9 ± 5 ‰ | 1.4 / 23.9 ‰ | 77 | bedded pyrite of the Urquhart Shale around the 1100 orebody Mean and standard deviation recalculated from 77 laminae, Table 2. Laminae under 2 mm sampled with a dentist drill, excluding crosscutting veins (pyrite 27.1 and chalcopyrite 20.2 ‰). Fine, little recrystallised pyrite I stays below 6 ‰ (sedimentary-diagenetic sulfur); recrystallised, coalescing pyrite rises to 20 to 24 ‰. | Andrew et al. (1989), Sulfur isotope systematics of copper ore formation at Mount Isa, Au… |
| 16.2 ± 3.6 ‰ | 12.2 / 21.2 ‰ | 7 | pyrite and pyrrhotite of chlorite schists (Eastern Creek metabasalts below the ore) Mean and standard deviation recalculated from 7 samples, Table 4. Altered, veined metabasalts, enriched in 34S relative to volcanics remote from the deposit. | Andrew et al. (1989), Sulfur isotope systematics of copper ore formation at Mount Isa, Au… |
| 23 ± 0.4 ‰ | 22.4 / 23.3 ‰ | 6 | chalcopyrite and pyrite of chlorite-albite-rutile schists (strongly altered metabasalts) Mean and standard deviation recalculated from 6 analyses, Table 4. The most sheared and copper-depleted rocks; values close to the ore fluid sulfur before its reaction with the Urquhart Shale. | Andrew et al. (1989), Sulfur isotope systematics of copper ore formation at Mount Isa, Au… |
| −7 / 3 ‰ | chalcopyrite and pyrite of Eastern Creek volcanics remote from the deposit Range quoted from unpublished data by Andrew, except one chalcopyrite at 11.6 ‰; consistent with unmodified igneous sulfur. | Andrew et al. (1989), Sulfur isotope systematics of copper ore formation at Mount Isa, Au… |
Deposits of the same type
- Flat Tyre Australia
- Watson's Lode Australia
- Lawn Hill discordant Zn-Pb-Ag lodes Australia
- Yankee Lodes Australia
- Elsmore Australia
- Tingha Australia
- Vegetable Creek (Emmaville) Australia
- Mole Granite (Torrington district) Australia
Cite this page
IsoFind Atlas (2026). Mount Isa (copper orebodies), isotope signatures. https://www.isofind.tech/isotopes/en/deposits/mount-isa-corps-mineralises-cuivreux/ (accessed 2026-10-13).
@misc{isofind2026mountisacopperorebodiesisotop,
title = {Mount Isa (copper orebodies), isotope signatures},
author = {{IsoFind Atlas}},
year = {2026},
url = {https://www.isofind.tech/isotopes/en/deposits/mount-isa-corps-mineralises-cuivreux/},
note = {Accessed 2026-10-13}
}Updated : 2026-10-13